Rotary electric machine

Abstract

To provide a highly reliable rotary electric machine that has sufficient resistance to demagnetization even in the event of a sudden short circuit while maintaining high output and high efficiency.SOLUTION: The rotary electric machine includes a stator and a rotor that is concentrically arranged inside the stator via a gap. In an axial view of the rotary electric machine, the rotor has multiple magnetic poles arranged in a circumferential direction. The magnetic poles have a first slot provided on the outer radial side and a second slot provided on the inner radial side. A first opposing part of first slot sides opposite to the second slot, has three or more obtuse angle bending points. A second opposing part of second slot side opposite to the first slot, has the same or more number of obtuse angle bending points than the first opposing part. A first magnet inserted into the first slot and a second magnet inserted into the second slot are arranged so that the distance from the gap becomes farther as it approaches the magnetic pole center line, and the further the second magnet is from the magnetic pole center, the narrower the width of the second magnet's magnetization direction becomes.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a rotating electric machine mounted on a railway vehicle, an automobile, a truck, a bus, a construction machine, and the like. [Background technology]

[0002] In order to achieve high output and high efficiency while making motors (rotating electric machines) small and lightweight, structures capable of increasing torque have been devised. Patent Document 1 discloses a rotating electric machine in which a two-layer magnetic pole is formed by an outer magnet arranged on the radially outer periphery side and an inner magnet arranged on the radially inner periphery side. The rotating electric machine described in Patent Document 1 aims to increase reluctance torque in addition to magnet torque by utilizing the magnetizing effect of the core part between the outer magnet and the inner magnet. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 7107243 Summary of the Invention [Problem to be solved by the invention]

[0004] A magnetic field that is opposite to the magnetization direction of a magnet is called a demagnetizing magnetic field, and when a demagnetizing magnetic field greater than the strength of magnetization (hereinafter referred to as the retentive force) is applied, the magnet is demagnetized and loses its original magnetic force. In a typical motor, the retentive force and magnetization width of the magnet are designed to have sufficient resistance to such a demagnetizing magnetic field (hereinafter referred to as the demagnetizing resistance). However, when a sudden short circuit (hereinafter referred to as the sudden short circuit) occurs during motor operation due to a decrease in insulation performance caused by aging of the motor windings, a broken electrical wiring, or a failure in the inverter circuit, a short circuit current is generated by the back electromotive force generated by the magnetic flux, which generates a massive demagnetizing magnetic field. With the conventional two-layer structure, it was difficult to ensure sufficient demagnetizing resistance to such a demagnetizing magnetic field.

[0005] An object of the present invention is to provide a highly reliable rotating electric machine that has sufficient demagnetization resistance even against a sudden short circuit while maintaining high output and high efficiency. [Means for solving the problem]

[0006] In order to achieve the above object, the present invention includes various embodiments. As an example, a rotating electric machine of the present invention is a rotating electric machine including a cylindrical stator and a rotor concentrically arranged inside the stator with a gap therebetween, and when viewed in the axial direction of the rotating electric machine, the rotor has a plurality of magnetic poles arranged in a circumferential direction, and the magnetic poles have a first slot provided on the radially outer side and a second slot provided on the radially inner side, the first slot and the second slot are each arranged symmetrically with respect to a magnetic pole center line, a first opposing portion of the side of the first slot facing the second slot has three or more obtuse angle bend points, and a second opposing portion of the side of the second slot facing the first slot has the same number of obtuse angle bend points as the bend points of the first opposing portion, a first magnet inserted in the first slot and a second magnet inserted in the second slot are arranged so that the closer they are to the magnetic pole center line, the farther they are from the gap, and the farther the second magnet is from the magnetic pole center line, the smaller the magnetization direction width of the second magnet becomes. Effect of the Invention

[0007] According to the present invention, it is possible to provide a highly reliable rotating electric machine that has sufficient demagnetization resistance even against a sudden short circuit while maintaining high output and high efficiency.

[0008] Problems, configurations and effects other than those described above will become apparent from the following description of the embodiments. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is an explanatory diagram of the overall structure of a rotating electric machine (motor) according to a first embodiment of the present invention. [Diagram 2]FIG. 2 is an explanatory diagram of a magnetic pole structure in the first embodiment of the present invention. [Figure 3A] FIG. 3A is an explanatory diagram of a magnetic pole structure in a second embodiment of the present invention. [Figure 3B] FIG. 3B is an enlarged view of magnet insertion holes 102, 202 of FIG. 3A, showing the dimensions of each magnet. [Figure 4] FIG. 4 is an explanatory diagram of a modified example of the magnet configuration in the second embodiment of the present invention. [Diagram 5] FIG. 5 is an explanatory diagram of a magnetic pole structure in a comparative example of this embodiment. [Figure 6A] FIG. 6A is a voltage-current vector diagram when the motor is running. [Figure 6B] FIG. 6B is a voltage-current vector diagram during a sudden short circuit. [Figure 7A] FIG. 7A is a diagram showing a magnetic pole structure in a comparative example of this embodiment, and shows a magnetic path when second magnet 220a and second magnet 220b have the same width in the magnetization direction. [Figure 7B] FIG. 7B is a diagram showing a magnetic pole structure in a comparative example of this embodiment, and shows a magnetic path when the width in the magnetization direction of second magnet 220a is larger than the width in the magnetization direction of second magnet 220b. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following description, the same components are given the same symbols. Their names and functions are the same, and duplicated explanations will be avoided. In addition, the following description is directed to a variable speed drive permanent magnet synchronous motor for automobiles, trucks, buses, etc., but the effects of the present invention are not limited to this and can be applied to all permanent magnet synchronous machines, including constant speed machines. EXAMPLES

[0011] A first embodiment of the present invention will be described below with reference to Figures 1 and 2. Figure 1 is an explanatory diagram of the overall structure of a rotating electric machine (motor) in the first embodiment of the present invention. Figure 2 is an explanatory diagram of the magnetic pole structure in the first embodiment of the present invention.

[0012] As shown in FIG. 1, the rotating electric machine 1 includes a cylindrical stator 10 and a rotor 20 that is concentrically disposed inside the stator 10 with a gap 21 therebetween. In the following description, a direction parallel to the central axis of rotation of the rotor 20 of the rotating electric machine 1 is referred to as an "axial direction", a diameter direction of the rotor 20 perpendicular to the central axis of rotation of the rotor 20 of the rotating electric machine 1 is referred to as a "radial direction", and a circumferential direction centered on the central axis of rotation of the rotor 20 of the rotating electric machine 1 is referred to as a "circumferential direction". FIGS. 1 and 2 are views of the rotating electric machine 1 as viewed from the axial direction. The shape, arrangement, size, etc. of each component of the rotating electric machine 1 as viewed from the axial direction will be described in detail below. As shown in the drawings, the rotor 20 has a plurality of magnetic poles 30 arranged in the circumferential direction.

[0013] As shown in FIG. 2, the magnetic pole 30 has a single first slot 100 provided on the radially outer periphery side and a single second slot 200 provided on the radially inner periphery side. The first slot 100 is a magnet slot into which a rectangular parallelepiped-shaped first magnet 120 is inserted. The second slot 200 is a magnet slot into which a rectangular parallelepiped-shaped second magnet 220 is inserted. The first slot 100 and the second slot 200 are each arranged line-symmetrically with respect to the magnetic pole center line (d-axis) 31. The pair of first magnets 120 inserted into the first slot 100 are arranged line-symmetrically with respect to the magnetic pole center line 31. Similarly, the two pairs of second magnets 220 inserted into the second slot 200 are arranged line-symmetrically with respect to the magnetic pole center line 31. The magnetic pole center line 31 is a line that extends radially from the rotation center axis and passes through the center of the magnetic pole 30.

[0014] In this embodiment, the first slot 100 and the second slot 200 have ribs 130, 230 at the position of the magnetic pole center line 31, respectively. In other words, the first slot 100 has a pair of magnet insertion holes (hereinafter, first magnet insertion holes) 102, and the second slot 200 has a pair of magnet insertion holes (hereinafter, second magnet insertion holes) 202. One first magnet 120 is inserted into the first magnet insertion hole 102, and two second magnets 220 are inserted into the second magnet insertion hole 202. The pair of first magnet insertion holes 102 are arranged at a predetermined inclination angle with respect to the magnetic pole center line 31. The first slot 100 has a line-symmetric shape with the magnetic pole center line 31 as the axis of symmetry, and has a V-shape that opens radially outward. Similarly, the pair of second magnet insertion holes 202 are arranged at a predetermined inclination angle with respect to the magnetic pole center line 31. The second slot 200 has an axisymmetric shape with respect to the magnetic pole center line 31 as an axis of symmetry, and has a V-shape that opens radially outward.

[0015] The ribs 130, 230 are provided for the purpose of preventing deformation of the first slot 100 and the second slot 200 due to centrifugal load. Note that the ribs 130, 230 do not necessarily have to be provided at these positions, and may be provided at other positions within the slots. Also, depending on the specifications of the rotating electric machine 1, the ribs 130, 230 may not be provided.

[0016] When viewed in the axial direction of the rotating electric machine 1, the first slot 100 has a plurality of sides. Among the plurality of sides constituting the first slot 100, a plurality of sides (hereinafter also referred to as opposing sides) opposing the second slot 200 form a first opposing portion 101 (see the dashed line in the figure). The first opposing portion 101 has three bend points 110 with obtuse angles. Note that the bend point 110 on the magnetic pole center line 31 corresponds to the end point on the lower side of the first opposing portion 101 in the figure when the rib 130 is omitted. In other words, the bend point 110 on the magnetic pole center line 31 corresponds to the intersection of the left opposing side of the right first magnet insertion hole 102 and the right opposing side of the left first magnet insertion hole 102.

[0017] Similarly, in the axial view of the rotating electric machine 1, the second slot 200 has a plurality of sides. Among the plurality of sides constituting the second slot 200, a plurality of sides (hereinafter also referred to as opposing sides) opposing the first slot 100 form a second opposing portion 201 (see the dashed line in the figure). The second opposing portion 201 has the same number (three) of obtuse angle bending points 210 as the bending points 110 of the first opposing portion 101. The bending point 210 on the magnetic pole center line 31 corresponds to the end point on the lower side of the second opposing portion 201 in the figure when the rib 230 is omitted. In other words, the bending point 210 on the magnetic pole center line 31 corresponds to the intersection of the left opposing side of the right second magnet insertion hole 202 and the right opposing side of the left second magnet insertion hole 202.

[0018] The first magnet 120 inserted into the first slot 100 and the second magnet 220 inserted into the second slot 200 are both magnetized in the direction of the arrow (→), and the magnetic poles 30 form N poles. The magnetization directions of the first magnet 120 and the second magnet 220 are reversed for each magnetic pole aligned in the circumferential direction. In other words, the magnetic pole 30 adjacent to the magnetic pole 30 shown in FIG. 2 forms a S pole.

[0019] Of the two pairs of second magnets 220 inserted into the second slot 200, the pair of second magnets 220 arranged near the magnetic pole center line 31 is referred to as second magnet 220a, and the pair of second magnets 220 arranged farther from the magnetic pole center line 31 than the second magnet 220a is referred to as second magnet 220b. The angle formed between the second magnet 220b and the magnetic pole center line 31 is smaller than the angle formed between the second magnet 220a and the magnetic pole center line 31. The angle formed between the second magnet 220 and the magnetic pole center line 31 refers to the angle formed radially outward (the smaller angle) of the intersection angles between the direction perpendicular to the magnetization direction of the second magnet 220 and the magnetic pole center line 31.

[0020] The following describes the effects obtained by using the structure of the rotating electric machine 1 according to the embodiment of the present invention through a comparison with a comparative example of this embodiment.

[0021] Fig. 5 is an explanatory diagram of a magnetic pole structure in a comparative example of this embodiment. As shown in Fig. 5, the magnetic pole 30 in the comparative example has a two-layer structure having a first slot 100 provided on the radially outer periphery side and a second slot 200 provided on the radially inner periphery side. The first slot 100 has only two obtuse angle bending points 110. Accordingly, the first magnet 120 is disposed perpendicular to the magnetic pole center line (d-axis) 31.

[0022] The second slot 200 has three obtuse-angle bending points 210. The second slot 200 has a pair of second magnets 220a arranged near the magnetic pole center line 31, and a pair of second magnets 220b arranged at a position farther from the magnetic pole center line 31 than the second magnets 220a. The angle formed between the second magnets 220b and the magnetic pole center line 31 is smaller than the angle formed between the second magnets 220a and the magnetic pole center line 31.

[0023] A magnetic field that is opposite to the magnetization direction of a magnet is called a demagnetizing magnetic field. When a demagnetizing magnetic field larger than the magnet's holding force is applied, the magnet is demagnetized and loses its original magnetic force. In a typical motor, the magnet's holding force and magnetization width are designed to have sufficient demagnetization resistance even against such a demagnetizing magnetic field. Figure 6A shows a voltage-current vector diagram when the motor is running, and Figure 6B shows a voltage-current vector diagram when a sudden short circuit occurs. For simplicity, the voltage drop corresponding to the motor winding resistance is omitted. In general, the center line of the magnetic pole of the motor is called the d-axis, and the axis that is 90° ahead of this in electrical angle is called the q-axis.

[0024] As shown in Figure 6A, the back electromotive force E0 generated by the magnet magnetic flux is generated on the q-axis, and the magnitude and phase of the voltage V applied to the motor are controlled so that it is balanced with the voltage drop (ωLI) caused by the magnetic flux generated by the motor current. In this state, the motor will not be demagnetized.

[0025] However, if a sudden short circuit occurs while the motor is running due to a deterioration in the insulation performance caused by aging of the motor windings, a broken electrical wiring, a failure in the inverter circuit, etc., the applied voltage V becomes zero. For this reason, as shown in Figure 6B, a short-circuit current I is generated in the negative d-axis direction to generate a voltage drop (ωLI) that balances with the back electromotive force E0, which generates an enormous demagnetizing magnetic field.

[0026] At this time, as shown in FIG. 5, the spatial distribution of the demagnetizing magnetic field in the gap 21 becomes sinusoidal with a peak on the d-axis (magnetic pole center line 31). Therefore, among the demagnetizing magnetic fields 50A to 50D, the strongest demagnetizing magnetic field is 50A, followed by 50B, 50C, and 50D in that order. In the structure of the comparative example, the first magnet 120 and the second magnet 220a exposed to the severe demagnetizing magnetic fields 50A and 50B near the magnetic pole center line 31, and the second magnet 220b exposed to the small demagnetizing magnetic fields 50C and 50D away from the magnetic pole center line 31 are all configured with approximately the same magnetization direction width (thickness). For this reason, it is difficult to ensure sufficient demagnetization resistance against the demagnetizing magnetic field generated at the time of sudden short circuit. In addition, the first magnet 120 is arranged perpendicular to the magnetic pole center line 31. That is, the distance from the gap 21 to the first magnet 120 in the circumferential direction is approximately the same. For this reason, it is difficult to ensure sufficient demagnetization resistance against the strongest demagnetizing magnetic field 50A generated in the vicinity of the magnetic pole center line 31.

[0027] In this way, the closer a magnet is placed to the magnetic pole center line 31, the stronger the demagnetizing magnetic field it is exposed to. Here, by making the magnet thicker or narrowing the width of the magnet in the direction perpendicular to its magnetization direction, the magnetic resistance of the magnet can be increased and the amount of reverse magnetic flux entering the magnet due to the demagnetizing magnetic field can be reduced.

[0028] Therefore, in the present embodiment, as shown in FIG. 2, the magnetization direction width (thickness) of the second magnet 220 is configured to decrease as the distance from the magnetic pole center line 31 increases. That is, the magnetization direction width T2a of the second magnet 220a disposed at a position closer to the magnetic pole center line 31 and the magnetization direction width T2b of the second magnet 220b disposed at a position farther from the magnetic pole center line 31 than the second magnet 220a are in the relationship of T2a>T2b. Thereby, the magnetic resistance of the second magnet 220a can be improved, so that the demagnetization resistance can be improved even against the large demagnetizing magnetic fields 50A and 50B.

[0029] In addition, in the axial view of the rotating electrical machine 1, the magnetization direction width T1 of the first magnet 120 and the smallest magnetization direction width (that is, the magnetization direction width of the second magnet 220b) T2b of the second magnet 220 may have a configuration in the relationship of T1>T2b. By making the thickness of the first magnet 120 thicker than that of the second magnet 220b and further increasing the magnetic resistance of the first magnet 120, the demagnetization resistance against the demagnetizing magnetic fields 50A and 50B can be further improved. Also, in the axial view of the rotating electrical machine 1, the magnet width W1 in the direction orthogonal to the magnetization direction of the first magnet 120 and the magnet width W2b in the direction orthogonal to the magnetization direction of the magnet (that is, the second magnet 220b) having the smallest magnetization direction width among the second magnets 220 may have a configuration in the relationship of W1<W2b. By making the magnet width W1 of the first magnet 120 smaller and further increasing the magnetic resistance of the first magnet 120, the demagnetization resistance against the demagnetizing magnetic fields 50A and 50B can be further improved. Note that the magnetization direction widths T1 and T2b and the magnet widths W1 and W2b may have a configuration in the relationship of T1>T2b and W1<W2b. Thereby, the magnetic resistance of the first magnet 120 can be improved, so that the demagnetization resistance can be improved even against the large demagnetizing magnetic fields 50A and 50B.

[0030] Furthermore, the first opposing portion 101 of the first slot 100 has three obtuse-angled bending points 110, and the second opposing portion 201 of the second slot 200 also has three obtuse-angled bending points 210. This allows the first magnet 120 and the second magnet 220 to be arranged so that the closer they are to the magnetic pole center line 31, the farther they are from the gap 21. Also, a space can be secured to make the magnetization direction width T2a of the second magnet 220a larger than the magnetization direction width T2b of the second magnet 220b. This allows the magnetization direction width (thickness) T2a of the second magnet 220a to be larger, and the total thickness (T1+T2a) of the first and second layers of magnets through which the demagnetization magnetic field 50A passes can be sufficiently secured. This allows the demagnetization resistance of the first magnet 120 and the second magnet 220a to be improved against the strongest demagnetization magnetic field 50A generated near the magnetic pole center line 31.

[0031] 7A and 7B, a problem that occurs when the number of bending points 210 of the second opposing portion 201 of the second slot 200 is less than three will be described. Fig. 7A is a diagram showing a magnetic pole structure in a comparative example of this embodiment, and shows a magnetic path when the magnetization direction width of the second magnet 220a and the second magnet 220b are equal. Fig. 7B is a diagram showing a magnetic pole structure in a comparative example of this embodiment, and shows a magnetic path when the magnetization direction width of the second magnet 220a is larger than the magnetization direction width of the second magnet 220b.

[0032] As shown in FIG. 7A, if the number of bending points 210 of the second opposing portion 201 of the second slot 200 is less than three (two in FIG. 7A), the configuration shown in FIG. 7B is obtained by increasing the magnetization direction width of the second magnet 220a. In this configuration, a magnetic path width L2 smaller than the magnetic path width L1 secured as a path for the q-axis magnetic flux 51 is generated. That is, the q-axis magnetic flux 51 required to generate reluctance torque is reduced, and sufficient torque cannot be generated. Therefore, in the comparative example, the configuration shown in FIG. 7B cannot be obtained, and the configuration shown in FIG. 7A is obtained, so that it is not possible to improve the demagnetization resistance by increasing the magnetization direction width of the second magnet 220a with respect to the strongest demagnetization magnetic field 50A generated in the vicinity of the magnetic pole center line 31.

[0033] As described above, in the first embodiment, the first opposing portion 101 of the side of the first slot 100 facing the second slot 200 has three obtuse-angle bend points 110, and the second opposing portion 201 of the side of the second slot 200 facing the first slot 100 has the same number of obtuse-angle bend points 210 as the bend points 110 of the first opposing portion 101. Also, the second magnet 220 is configured such that the magnetization direction width of the second magnet 220 decreases as the distance from the magnetic pole center line 31 increases. This makes it possible to provide a highly reliable rotating electric machine (motor) 1 that has sufficient demagnetization resistance even against a sudden short circuit while maintaining high output and high efficiency.

[0034] As another embodiment of the above configuration, the ratio (T / W) of the magnet width T in the magnetization direction to the magnet width W in the direction perpendicular to the magnetization direction may be defined as the aspect ratio R, and the aspect ratio R2a (=T2a / W2a) of the second magnet 220a may be larger than the aspect ratio R2b (=T2b / W2b) of the second magnet 220b. For example, the magnet width W2a of the second magnet 220a may be smaller than the magnet width W2b of the second magnet 220b, thereby satisfying R2a>R2b. In this case, the relationship between the magnetization width T2a of the second magnet 220a and the magnetization width T2b of the second magnet 220b may be T2a≦T2b. In addition, the aspect ratio R1 (=T1 / W1) of the first magnet 120 may be larger than the aspect ratio R2b of the second magnet 220b. For example, the magnet width W1 of the first magnet 120 can be made smaller than the magnet width W2b of the second magnet 220b to satisfy R1>R2b. In this case, the relationship between the magnetization direction width T1 of the first magnet 120 and the magnetization direction width T2b of the second magnet 220b may be T1≦T2b. EXAMPLES

[0035] A second embodiment of the present invention will be described with reference to Figures 3A and 3B. Figure 3A is an explanatory diagram of the magnetic pole structure in the second embodiment of the present invention, and the difference from Figure 2 is the shape of the magnet insertion holes and the arrangement of the magnets. Figure 3B is an enlarged view of magnet insertion holes 102, 202 in Figure 3A, showing the dimensions of each magnet.

[0036] As shown in Fig. 5, the second slot 200 has a wider circumferential width than the first slot 100, and the position dependency of the demagnetization magnetic field is large. In the first embodiment, an example was described in which the magnetization direction width of the second magnet 220 inserted into the second slot 200 is increased as the magnetization direction width approaches the magnetic pole center line 31, as shown in Fig. 2, as a method for improving the demagnetization resistance against the demagnetization magnetic fields 50A and 50B. In contrast, in the second embodiment, the magnetization direction width of not only the second magnet 220 but also the first magnet 120 inserted into the first slot 100 is increased as the magnetization direction width approaches the magnetic pole center line 31, thereby further improving the demagnetization resistance. The second embodiment will be described in detail below.

[0037] 3A and 3B, when viewed in the axial direction of the rotating electric machine 1, the first magnet 120 inserted into the first slot 100 is configured so that the magnetization direction width of the first magnet 120 decreases as the distance from the magnetic pole center line 31 increases. In other words, the magnetization direction width T1a of the first magnet 120a arranged at a position closer to the magnetic pole center line 31 is configured to be larger than the magnetization direction width T1b of the first magnet 120b arranged at a position farther from the magnetic pole center line 31 than the first magnet 120a (T1a>T1b).

[0038] Moreover, the second magnet 220 inserted into the second slot 200 is configured such that the magnetization direction width of the second magnet 220 decreases as the distance from the magnetic pole center line 31 increases. In the illustrated example, three second magnets 220 are inserted into the second magnet insertion hole 202. Below, the second magnets 220 will be referred to with the symbols a, b, and c in order of proximity to the magnetic pole center line 31.

[0039] The magnetization direction width T2b of the second magnet 220b is configured to be larger than the magnetization direction width T2c of the second magnet 220c (T2b>T2c). Furthermore, the magnetization direction width T2a of the second magnet 220a is configured to be equal to or larger than the magnetization direction width T2b of the second magnet 220b (T2a≧T2b). This can improve the magnetic resistance of the first magnet 120a and the second magnets 220a and 220b, thereby improving the demagnetization resistance against the severe demagnetization magnetic fields 50A and 50B (see FIG. 5).

[0040] In addition, the first opposing portion 101 of the first slot 100 has seven obtuse-angled bending points 110. Similarly, the second opposing portion 201 of the second slot 200 has the same number (seven) of obtuse-angled bending points 210 as the bending points 110 of the first opposing portion. This allows a space to be secured for making the magnetization direction width T1a of the first magnet 120a larger than the magnetization direction width T1b of the first magnet 120b. Similarly, a space to make the magnetization direction width larger in the order of the second magnets 220c, 220b, and 220a can be secured. Furthermore, by increasing the number of bending points 110 of the first slot 100 and the bending points 210 of the second slot 200, the magnetization direction widths of the first magnet 120 and the second magnet 220 can be set finely according to the distance from the magnetic pole center line 31. This allows the demagnetization resistance to be improved without excess or deficiency.

[0041] As another embodiment of the above configuration, the aspect ratios R2a (=T2a / W2a), R2b (=T2b / W2b), and R2c (=T2c / W2c) of the second magnets 220a, 220b, and 220c may be configured to satisfy the relationship R2a ≧ R2b > R2c. In addition, the aspect ratios R1a (=T1a / W1a), R1b (=T1b / W1b), and R2c of the first magnets 120a, 120b and the second magnet 220c may be configured to satisfy the relationship R1a > R1b ≧ R2c.

[0042] The following modified examples are also within the scope of the present invention, and it is possible to combine the configurations shown in the modified examples with the configurations described in the above-mentioned embodiments, to combine the configurations described in the different embodiments above, or to combine the configurations described in the different modified examples below.

[0043] <Variation 1> However, when multiple magnets with different magnetization widths are used, magnet costs increase. Therefore, for example, as shown in FIG. 4, a magnet is constructed by combining basic rectangular parallelepiped unit magnets 40 in the radial and circumferential directions. This makes it possible to avoid an increase in magnet costs. FIG. 4 is an explanatory diagram of a modified magnet configuration in the second embodiment described above. The shapes of the first slot 100 and the second slot 200 in this modified example are the same as those in the second embodiment (see FIG. 3A). This modified example differs from the second embodiment in that, as viewed in the axial direction of the rotating electric machine 1, the first magnet 120 and the second magnet 220 each consist of two or more unit magnets 40 having a basic shape.

[0044] In this modification, the first magnet 120a is made up of three unit magnets 40 stacked in the magnetization direction. The first magnet 120b is made up of two unit magnets 40 stacked in the magnetization direction. The second magnet 220a is made up of three unit magnets 40 stacked in the magnetization direction, arranged in two rows in a direction perpendicular to the magnetization direction. Similarly, the second magnet 220b is made up of three unit magnets 40 stacked in the magnetization direction, arranged in two rows in a direction perpendicular to the magnetization direction. The second magnet 220c is made up of two unit magnets 40 stacked in the magnetization direction.

[0045] The magnetization direction width T1a of the first magnet 120a is a dimension equivalent to three times the magnetization direction width (thickness) t of the unit magnet 40 (T1a=3×t). The magnetization direction widths T1b, T2c of the first magnet 120b and the second magnet 220c are a dimension equivalent to twice the magnetization direction width (thickness) t of the unit magnet 40 (T1b=T2c=2×t). The magnetization direction widths T2a, T2b of the second magnets 220a, 220b are a dimension equivalent to three times the magnetization direction width (thickness) of the unit magnet 40 (T2a=T2b=3×t). Thus, in this modification, the magnetization direction widths of the first magnet 120 and the second magnet 220 are determined by the number of unit magnets 40 inserted into the first slot 100 and the second slot 200 as viewed in the axial direction of the rotating electric machine 1.

[0046] The magnet widths W2a, W2b in the direction perpendicular to the magnetization direction of the second magnet 220a and the second magnet 220b are dimensions equivalent to twice the magnet width w in the direction perpendicular to the magnetization direction of the unit magnet 40 (W2a = W2b = 2 × w). Thus, in this modified example, when viewed in the axial direction of the rotating electric machine 1, the magnet width in the direction perpendicular to the magnetization direction of the first magnet 120 and the second magnet 220 is determined by the number of unit magnets 40 inserted into the first slot 100 and the second slot 200.

[0047] In addition, in this modified example, when viewed in the axial direction of the rotating electric machine 1, the dimensions of the unit magnets 40 (magnetization direction width and magnet width perpendicular to the magnetization direction) are determined so that the number of unit magnets 40 included in the magnetic pole 30 is minimized.

[0048] Such a configuration makes it possible to maintain an appropriate number of parts and management costs while using the same magnets. Therefore, according to this modification, it is possible to provide a highly reliable rotating electric machine (motor) 1 at low cost that has sufficient demagnetization resistance even against sudden short circuits while maintaining high output and high efficiency.

[0049] In the example shown in Fig. 4, an example has been described in which the dimensions of the unit magnets 40 are determined so that the number of unit magnets 40 included in the magnetic pole 30 is minimized, but the method of determining the dimensions of the unit magnets 40 is not limited to this. For example, the magnetization direction width (thickness) of the unit magnets 40 may be halved, or the magnet width perpendicular to the magnetization direction of the unit magnets 40 may be halved, compared to the example shown in Fig. 4. However, in this case, the number of unit magnets 40 will be large, so as described above, it is preferable to determine the dimensions of the unit magnets 40 so that the number of unit magnets 40 included in the magnetic pole 30 is minimized.

[0050] The shapes, sizes, and positional relationships of the unit magnets 40, the first magnet 120, and the second magnet 220 can be in various modes. Although not shown, for example, the first magnet 120b and the second magnet 220c may each be composed of one unit magnet 40, and the first magnet 120a, the second magnet 220a, and the second magnet 220b may each be composed of two or more unit magnets 40. In other words, the first magnet 120 and the second magnet 220 can each be composed of one or more unit magnets 40 having a basic shape.

[0051] <Variation 2> The number of first magnets 120 and second magnets 220 constituting the magnetic pole 30 is not limited to the above-mentioned example. The number of bending points 110, 210 of the first opposing portion 101 and the second opposing portion 201 is also not limited to the above-mentioned example. It is sufficient that the first opposing portion 101 has at least three obtuse-angle bending points 110, and the second opposing portion 201 has the same number of obtuse-angle bending points 210 as the bending points 110 of the first opposing portion 101 or more.

[0052] Although the embodiments of the present invention have been described above, the above-mentioned embodiments merely show some of the application examples of the present invention, and it is not intended that the technical scope of the present invention be limited to the specific configurations of the above-mentioned embodiments. [Explanation of symbols]

[0053] 1: Rotating electric machine 10: Stator 20:Rota 21: Gap 30: Magnetic pole 31: Magnetic pole center line (d axis) 40: Unit magnet 50: Demagnetizing magnetic field 100: First slot 101: First opposing part 102: First magnet insertion hole 110: Bend point of obtuse angle of first opposing portion 120: First magnet 130: First slot rib 200: Second slot 201: Second opposing part 202: Second magnet insertion hole 210: Bend point of obtuse angle of second opposing portion 220:Second magnet 230: Rib of second slot

Claims

1. A rotating electric machine including a cylindrical stator and a rotor concentrically disposed inside the stator with a gap therebetween, When viewed in the axial direction of the rotating electric machine, the rotor has a plurality of magnetic poles arranged in a circumferential direction, the magnetic poles have first slots provided on the radially outer periphery side and second slots provided on the radially inner periphery side, the first slots and the second slots are each arranged symmetrically with respect to a magnetic pole center line, a first opposing portion of a side of the first slot that faces the second slot has three or more obtuse angle bend points, and a second opposing portion of a side of the second slot that faces the first slot has the same number of obtuse angle bend points as the bend points of the first opposing portion, or more; a first magnet inserted into the first slot and a second magnet inserted into the second slot are arranged such that the closer to the magnetic pole center line the first magnet is, the farther the magnet is from the gap; A rotating electric machine comprising: the second magnet, the width of which in the magnetization direction becomes smaller as the distance from the magnetic pole center line increases.

2. 2. The rotating electric motor according to claim 1, characterized in that, when viewed in the axial direction of the rotating electric motor, the magnetization direction width T1 of the first magnet and the smallest magnetization direction width T2 of the second magnet have a relationship of T1 > T2.

3. 2. The rotating electric machine according to claim 1, characterized in that, when viewed in the axial direction of the rotating electric machine, a magnet width W1 in a direction perpendicular to the magnetization direction of the first magnet and a magnet width W2 in a direction perpendicular to the magnetization direction of the magnet having the smallest magnetization direction width among the second magnets have a relationship of W1 < W2.

4. 2. The rotating electric machine according to claim 1, characterized in that, when viewed in the axial direction of the rotating electric machine, the magnetization direction width of the first magnet becomes smaller as the distance from the magnetic pole center line increases.

5. The rotating electric machine according to claim 1 , characterized in that, when viewed in the axial direction of the rotating electric machine, the first magnet and the second magnet each consist of one or more unit magnets having a basic shape.

6. 6. The rotating electric machine according to claim 5, characterized in that, when viewed in the axial direction of the rotating electric machine, the magnetization direction width of the first magnet and the second magnet is determined by the number of unit magnets inserted into the first slot and the second slot.

7. 6. The rotating electric machine according to claim 5, characterized in that, when viewed in the axial direction of the rotating electric machine, the magnet width in a direction perpendicular to the magnetization direction of the first magnet and the second magnet is determined by the number of unit magnets inserted into the first slot and the second slot.

8. 6. The rotating electric machine according to claim 5, wherein, when viewed in the axial direction of the rotating electric machine, the dimensions of the unit magnets are determined so as to minimize the number of the unit magnets included in the magnetic pole.

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